Re: Reliability with RAID 10 SSD and Streaming Replication

Hi,

On 16.5.2013 16:46, Cuong Hoang wrote:
> Hi all,
>
> Our application is heavy write and IO utilisation has been the problem
> for us for a while. We've decided to use RAID 10 of 4x500GB Samsung 840

What does "heavy write" mean in your case? Does that mean a lot of small
transactions or few large ones?

What have you done to tune the server?

> Pro for the master server. I'm aware of write cache issue on SSDs in
> case of power loss. However, our hosting provider doesn't offer any
> other choices of SSD drives with supercapacitor. To minimise risk, we
> will also set up another RAID 10 SAS in streaming replication mode. For
> our application, a few seconds of data loss is acceptable.

Streaming replication allows zero data loss if used in synchronous mode.

> My question is, would corrupted data files on the primary server affect
> the streaming standby? In other word, is this setup acceptable in terms
> of minimising deficiency of SSDs?

It should be.

Have you considered using a UPS? That would make the SSDs about as
reliable as SATA/SAS drives - the UPS may fail, but so may a BBU unit on
the SAS controller.

Tomas